OBJECTIVE: To study the role of lipids in the structure and function of membranes of mouse C1300 neuroblastoma during differentiation in vitro. APPROACH: The problem is being examined from three interrelated points of view. Dr. Peter Jones is determining the lipid composition of neuroblastoma cells preliminary to studying the control of lipid metabolism during differentiation. Dr. William Struve is examining changes in membrane structure during neuroblastoma differentiation using the spin label technique. The label currently being used is 5-doxylstearic acid. Dr. Richard Arneson is attempting to isolate and characterize antioxidant factors present in the differentiated form of neuroblastoma. These factors prevent the peroxidation of membrane lipids. Both the thiobarbituric acid test and fatty acid analysis by gas chromatography are used to estimate the extent of lipid peroxidation.